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Jiao J, Hu B, Mou T, Li Q, Tian Y, Zhang N, Zhang Y, Yun M, Nan N, Tian J, Yu W, Mi H, Dong W, Song X. Translocator Protein 18 kDa Tracer 18F-FDPA PET/CTA Imaging for the Evaluation of Inflammation in Vulnerable Plaques. Mol Pharm 2024; 21:3623-3633. [PMID: 38819959 DOI: 10.1021/acs.molpharmaceut.4c00344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Inflammation induced by activated macrophages within vulnerable atherosclerotic plaques (VAPs) constitutes a significant risk factor for plaque rupture. Translocator protein (TSPO) is highly expressed in activated macrophages. This study investigated the effectiveness of TSPO radiotracers, 18F-FDPA, in detecting VAPs and quantifying plaque inflammation in rabbits. 18 New Zealand rabbits were divided into 3 groups: sham group A, VAP model group B, and evolocumab treatment group C. 18F-FDPA PET/CTA imaging was performed at 12, 16, and 24 weeks in all groups. Optical coherence tomography (OCT) was performed on the abdominal aorta at 24 weeks. The VAP was defined through OCT images, and ex vivo aorta PET imaging was also performed at 24 weeks. The SUVmax and SUVmean of 18F-FDPA were measured on the target organ, and the target-to-background ratio (TBRmax) was calculated as SUVmax/SUVblood pool. The arterial sections of the isolated abdominal aorta were analyzed by HE staining, CD68 and TSPO immunofluorescence staining, and TSPO Western blot. The results showed that at 24 weeks, the plaque TBRmax of 18F-FDPA in group B was significantly higher than in groups A and C. Immunofluorescence staining of CD68 and TSPO, as well as Western blot, confirmed the increased expression of macrophages and TSPO in the corresponding regions of group B. HE staining revealed an increased presence of the lipid core, multiple foam cells, and inflammatory cell infiltration in the area with high 18F-FDPA uptake. This indicates a correlation between 18F-FDPA uptake, inflammation severity, and VAPs. The TSPO-targeted tracer 18F-FDPA shows specific uptake in macrophage-rich regions of atherosclerotic plaques, making it a valuable tool for assessing inflammation in VAPs.
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Affiliation(s)
- Jian Jiao
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Biao Hu
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Tiantian Mou
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Quan Li
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Yi Tian
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Nan Zhang
- Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Ying Zhang
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Mingkai Yun
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Nan Nan
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Jing Tian
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Wei Yu
- Department of Pathology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Hongzhi Mi
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Wei Dong
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
| | - Xiantao Song
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, China
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Uzuegbunam BC, Rummel C, Librizzi D, Culmsee C, Hooshyar Yousefi B. Radiotracers for Imaging of Inflammatory Biomarkers TSPO and COX-2 in the Brain and in the Periphery. Int J Mol Sci 2023; 24:17419. [PMID: 38139248 PMCID: PMC10743508 DOI: 10.3390/ijms242417419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Inflammation involves the activation of innate immune cells and is believed to play an important role in the development and progression of both infectious and non-infectious diseases such as neurodegeneration, autoimmune diseases, pulmonary and cancer. Inflammation in the brain is marked by the upregulation of translocator protein (TSPO) in microglia. High TSPO levels are also found, for example, in macrophages in cases of rheumatoid arthritis and in malignant tumor cells compared to their relatively low physiological expression. The same applies for cyclooxgenase-2 (COX-2), which is constitutively expressed in the kidney, brain, thymus and gastrointestinal tract, but induced in microglia, macrophages and synoviocytes during inflammation. This puts TSPO and COX-2 in the spotlight as important targets for the diagnosis of inflammation. Imaging modalities, such as positron emission tomography and single-photon emission tomography, can be used to localize inflammatory processes and to track their progression over time. They could also enable the monitoring of the efficacy of therapy and predict its outcome. This review focuses on the current development of PET and SPECT tracers, not only for the detection of neuroinflammation, but also for emerging diagnostic measures in infectious and other non-infectious diseases such as rheumatic arthritis, cancer, cardiac inflammation and in lung diseases.
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Affiliation(s)
| | - Christoph Rummel
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University Giessen, 35392 Gießen, Germany;
- Center for Mind Brain and Behavior, Universities Giessen and Marburg, 35043 Marburg, Germany;
| | - Damiano Librizzi
- Department of Nuclear Medicine, Philipps University of Marburg, 35043 Marburg, Germany;
| | - Carsten Culmsee
- Center for Mind Brain and Behavior, Universities Giessen and Marburg, 35043 Marburg, Germany;
- Institute of Pharmacology and Clinical Pharmacy, Philipps University of Marburg, 35037 Marburg, Germany
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Haveman LYF, Vugts DJ, Windhorst AD. State of the art procedures towards reactive [ 18F]fluoride in PET tracer synthesis. EJNMMI Radiopharm Chem 2023; 8:28. [PMID: 37824021 PMCID: PMC10570257 DOI: 10.1186/s41181-023-00203-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/03/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Positron emission tomography (PET) is a powerful, non-invasive preclinical and clinical nuclear imaging technique used in disease diagnosis and therapy assessment. Fluorine-18 is the predominant radionuclide used for PET tracer synthesis. An impressive variety of new 'late-stage' radiolabeling methodologies for the preparation of 18F-labeled tracers has appeared in order to improve the efficiency of the labeling reaction. MAIN BODY Despite these developments, one outstanding challenge into the early key steps of the process remains: the preparation of reactive [18F]fluoride from oxygen-18 enriched water ([18O]H2O). In the last decade, significant changes into the trapping, elution and drying stages have been introduced. This review provides an overview of the strategies and recent developments in the production of reactive [18F]fluoride and its use for radiolabeling. CONCLUSION Improved, modified or even completely new fluorine-18 work-up procedures have been developed in the last decade with widespread use in base-sensitive nucleophilic 18F-fluorination reactions. The many promising developments may lead to a few standardized drying methodologies for the routine production of a broad scale of PET tracers.
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Affiliation(s)
- Lizeth Y F Haveman
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam, The Netherlands
| | - Danielle J Vugts
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Cancer Center Amsterdam (CCA), Amsterdam, The Netherlands
| | - Albert D Windhorst
- Radiology and Nuclear Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
- Neuroscience Amsterdam, Amsterdam, The Netherlands.
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Chassé M, Pees A, Lindberg A, Liang SH, Vasdev N. Spirocyclic Iodonium Ylides for Fluorine-18 Radiolabeling of Non-Activated Arenes: From Concept to Clinical Research. CHEM REC 2023; 23:e202300072. [PMID: 37183954 DOI: 10.1002/tcr.202300072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/27/2023] [Indexed: 05/16/2023]
Abstract
Positron emission tomography (PET) is a powerful imaging tool for drug discovery, clinical diagnosis, and monitoring of disease progression. Fluorine-18 is the most common radionuclide used for PET, but advances in radiotracer development have been limited by the historical lack of methodologies and precursors amenable to radiolabeling with fluorine-18. Radiolabeling of electron-rich (hetero)aromatic rings remains a long-standing challenge in the production of PET radiopharmaceuticals. In this personal account, we discuss the history of spirocyclic iodonium ylide precursors, from inception to applications in clinical research, for the incorporation of fluorine-18 into complex non-activated (hetero)aromatic rings.
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Affiliation(s)
- Melissa Chassé
- Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, ON M5S 1A8, Canada
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Anna Pees
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Anton Lindberg
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, 30322, USA
| | - Neil Vasdev
- Institute of Medical Science, University of Toronto, 1 Kings College Circle, Toronto, ON M5S 1A8, Canada
- Azrieli Centre for Neuro-Radiochemistry, Brain Health Imaging Centre, Centre for Addiction and Mental Health (CAMH), 250 College Street, Toronto, ON M5T 1R8, Canada
- Department of Psychiatry, University of Toronto, 250 College Street, Toronto, ON M5T 1R8, Canada
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Rong J, Haider A, Jeppesen TE, Josephson L, Liang SH. Radiochemistry for positron emission tomography. Nat Commun 2023; 14:3257. [PMID: 37277339 PMCID: PMC10241151 DOI: 10.1038/s41467-023-36377-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 01/30/2023] [Indexed: 06/07/2023] Open
Abstract
Positron emission tomography (PET) constitutes a functional imaging technique that is harnessed to probe biological processes in vivo. PET imaging has been used to diagnose and monitor the progression of diseases, as well as to facilitate drug development efforts at both preclinical and clinical stages. The wide applications and rapid development of PET have ultimately led to an increasing demand for new methods in radiochemistry, with the aim to expand the scope of synthons amenable for radiolabeling. In this work, we provide an overview of commonly used chemical transformations for the syntheses of PET tracers in all aspects of radiochemistry, thereby highlighting recent breakthrough discoveries and contemporary challenges in the field. We discuss the use of biologicals for PET imaging and highlight general examples of successful probe discoveries for molecular imaging with PET - with a particular focus on translational and scalable radiochemistry concepts that have been entered to clinical use.
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Affiliation(s)
- Jian Rong
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA, 30322, USA
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Ahmed Haider
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA, 30322, USA
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Troels E Jeppesen
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Lee Josephson
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA
| | - Steven H Liang
- Department of Radiology and Imaging Sciences, Emory University, 1364 Clifton Rd, Atlanta, GA, 30322, USA.
- Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital & Department of Radiology, Harvard Medical School, Boston, MA, 02114, USA.
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6
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Wei H, Wei J, Zhang S, Dong S, Li G, Ran W, Dong C, Zhang W, Che C, Luo W, Xu H, Dong Z, Wang J, Wang L. Easily automated radiosynthesis of [18F]P10A-1910 and its clinical translation to quantify phosphodiesterase 10A in human brain. Front Bioeng Biotechnol 2022; 10:983488. [PMID: 36147528 PMCID: PMC9486304 DOI: 10.3389/fbioe.2022.983488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Our previous work showed that [18F]P10A-1910 was a potential radioligand for use in imaging phosphodiesterase 10A (PDE10A). Specifically, it had high brain penetration and specific binding that was demonstrated in both rodents and non-human primates. Here, we present the first automatic cGMP-level production of [18F]P10A-1910 and translational PET/MRI study in living human brains. Successful one-step radiolabeling of [18F]P10A-1910 on a GE TRACERlab FX2N synthesis module was realized via two different methods. First, formulated [18F]P10A-1910 was derived from heating spirocyclic iodonium ylide in a tetra-n-butyl ammonium methanesulfonate solution. At the end of synthesis, it was obtained in non-decay corrected radiochemical yields (n.d.c. RCYs) of 12.4 ± 1.3%, with molar activities (MAs) of 90.3 ± 12.6 μmol (n = 7) (Method I). The boronic pinacol ester combined with copper and oxygen also delivered the radioligand with 16.8 ± 1.0% n. d.c. RCYs and 77.3 ± 20.7 GBq/μmol (n = 7) MAs after formulation (Method II). The radiochemical purity, radionuclidic purity, solvent residue, sterility, endotoxin content and other parameters were all validated for human use. Consistent with the distribution of PDE10A in the brain, escalating uptake of [18F]P10A-1910 was observed in the order of cerebellum (reference region), substantial nigra, caudate and putamen. The non-displaceable binding potential (BPND) was estimated by simplified reference-tissue model (SRTM); linear regressions demonstrated that BPND was well correlated with the most widely used semiquantitative parameter SUV. The strongest correlation was observed with SUV(50–60 min) (R2 = 0.966, p < 0.01). Collectively, these results indicated that a static scan protocol could be easily performed for PET imaging of PDE10A. Most importantly, that [18F]P10A-1910 is a promising radioligand to clinically quantify PDE10A.
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Affiliation(s)
- Huiyi Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Junjie Wei
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shaojuan Zhang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shiliang Dong
- Center of Bariatric Surgery, Department of Gastrointestinal Surgery, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Guocong Li
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Wenqing Ran
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Chenchen Dong
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Weibin Zhang
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Chao Che
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Wenzhao Luo
- Institute of Analysis, Guangdong Academy of Sciences (China National Analytical Center), Guangzhou, China
| | - Hao Xu
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Zhiyong Dong
- Center of Bariatric Surgery, Department of Gastrointestinal Surgery, The First Affiliated Hospital of Jinan University, Guangzhou, China
- The Guangzhou Key Laboratory of Basic and Translational Research on Chronic Diseases, The First Affiliated Hospital of Jinan University, Guangzhou, China
- *Correspondence: Lu Wang, ; Jinghao Wang, ; Zhiyong Dong,
| | - Jinghao Wang
- The Guangzhou Key Laboratory of Basic and Translational Research on Chronic Diseases, The First Affiliated Hospital of Jinan University, Guangzhou, China
- Department of Pharmacy, The First Affiliated Hospital of Jinan University, Guangzhou, China
- *Correspondence: Lu Wang, ; Jinghao Wang, ; Zhiyong Dong,
| | - Lu Wang
- Center of Cyclotron and PET Radiopharmaceuticals, Department of Nuclear Medicine, The First Affiliated Hospital of Jinan University, Guangzhou, China
- The Guangzhou Key Laboratory of Basic and Translational Research on Chronic Diseases, The First Affiliated Hospital of Jinan University, Guangzhou, China
- *Correspondence: Lu Wang, ; Jinghao Wang, ; Zhiyong Dong,
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China’s radiopharmaceuticals on expressway: 2014–2021. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2021-1137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
This review provides an essential overview on the progress of rapidly-developing China’s radiopharmaceuticals in recent years (2014–2021). Our discussion reflects on efforts to develop potential, preclinical, and in-clinical radiopharmaceuticals including the following areas: (1) brain imaging agents, (2) cardiovascular imaging agents, (3) infection and inflammation imaging agents, (4) tumor radiopharmaceuticals, and (5) boron delivery agents (a class of radiopharmaceutical prodrug) for neutron capture therapy. Especially, the progress in basic research, including new radiolabeling methodology, is highlighted from a standpoint of radiopharmaceutical chemistry. Meanwhile, we briefly reflect on the recent major events related to radiopharmaceuticals along with the distribution of major R&D forces (universities, institutions, facilities, and companies), clinical study status, and national regulatory supports. We conclude with a brief commentary on remaining limitations and emerging opportunities for China’s radiopharmaceuticals.
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8
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State of the art of radiochemistry for 11C and 18F PET tracers. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00007-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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9
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Mi X, Pi C, Feng W, Cui X. Recent progress in the application of iodonium ylides in organic synthesis. Org Chem Front 2022. [DOI: 10.1039/d2qo01332k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This review summarizes the recent advances in the synthetic application of iodonium ylides covering 2017 to 2022.
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Affiliation(s)
- Xia Mi
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, P. R. China
| | - Chao Pi
- College of Chemistry, Green Catalysis Center, Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou 450052, P. R. China
| | - Weisheng Feng
- College of Pharmacy, Henan University of Chinese Medicine, Zhengzhou 450046, P. R. China
| | - Xiuling Cui
- College of Chemistry, Green Catalysis Center, Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Zhengzhou University, Zhengzhou 450052, P. R. China
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10
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Childs MD, Yu L, Kovacs MS, Luyt LG. Radiofluorination of non-activated aromatic prosthetic groups for synthesis and evaluation of fluorine-18 labelled ghrelin(1-8) analogues. Org Biomol Chem 2021; 19:8812-8820. [PMID: 34590643 DOI: 10.1039/d1ob01023a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The growth hormone secretagogue receptor 1a (GHSR) is differentially expressed in various disease states compared to healthy tissues and thus is a target for molecular imaging. The endogenous ligand for the GHSR is ghrelin, a 28 amino acid peptide with a unique octanoyl group on the serine-3 residue. A recently reported ghrelin analogue revealed the successful use of fluorine-containing, polycyclic aromatic groups in place of the octanoyl side chain, thereby providing potential access to new 18F-PET imaging probes. The peptide [Inp1,Dpr3(6-FN),1Nal4,Thr8]ghrelin(1-8) amide (1) showed sub-nanomolar receptor affinity (IC50 = 0.11 nM) toward the GHSR making it the strongest affinity ghrelin analogue reported to date. However, attempts to label such non-activated aromatic groups with fluoride-18 through conventional substitution methods resulted in low radiochemical yields, impractical for use in vivo. Since larger, non-activated aromatic groups appear to be of value for incorporating fluorine into ghrelin(1-8) analogues, an additional peptide bearing a 4'-fluorobiphenyl-4-carboxyl (4'-FBC) group in place of the octanoyl side chain was also of interest. Herein, we describe the radiosynthesis of [Inp1,Dpr3([18F]6-FN),1Nal4,Thr8]ghrelin(1-8) amide ([18F]1) and [Inp1,Dpr3([18F]4'-FBC),1Nal4,Thr8]ghrelin(1-8) amide ([18F]2) using a prosthetic group approach from iodonium ylide precursors as well as initial in vitro and in vivo evaluation of [18F]1 as a potential PET tracer for targeted imaging of the GHSR.
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Affiliation(s)
- Marina D Childs
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3 K7, Canada.
| | - Lihai Yu
- London Regional Cancer Program, Lawson Health Research Institute, 800 Commissioners Road East, London, Ontario, N6A 4L6, Canada
| | - Michael S Kovacs
- Department of Medical Imaging, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3 K7, Canada.,Department of Medical Biophysics, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3 K7, Canada.,Lawson Cyclotron & PET Radiochemistry Facility, Lawson Health Research Institute, 268 Grosvenor Street, London, Ontario, N6A 5 W9, Canada
| | - Leonard G Luyt
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3 K7, Canada. .,London Regional Cancer Program, Lawson Health Research Institute, 800 Commissioners Road East, London, Ontario, N6A 4L6, Canada.,Department of Medical Imaging, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3 K7, Canada.,Department of Oncology, University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 3 K7, Canada
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11
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Mou T, Tian J, Tian Y, Yun M, Li J, Dong W, Lu X, Zhu Z, Mi H, Zhang X, Li X. Automated synthesis and preliminary evaluation of [ 18F]FDPA for cardiac inflammation imaging in rats after myocardial infarction. Sci Rep 2020; 10:18685. [PMID: 33122775 PMCID: PMC7596090 DOI: 10.1038/s41598-020-75705-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 10/19/2020] [Indexed: 11/26/2022] Open
Abstract
A translocator protein 18 kDa targeted radiotracer, N,N-diethyl-2-(2-(4-[18F]fluorophenyl)-5,7-dimethylpyrazolo[1,5-a] pyrimidin-3-yl) acetamide ([18F]FDPA), was automated synthetized and evaluated for cardiac inflammation imaging. Various reaction conditions for an automated synthesis were systematically optimized. MicroPET/CT imaging were performed on normal rats and rats with myocardial infarction (MI). Normalized SUV ratios of [18F]FDPA to [13N]NH3 (NSRs) in different regions were calculated to normalize the uptake of [18F]FDPA to perfusion. The amount of TBAOMs and the volume/proportion of water were crucial for synthesis. After optimization, the total synthesis time was 68 min. The non-decay corrected radiochemical yields (RCYs) and molar activities were 19.9 ± 1.7% and 169.7 ± 46.5 GBq/μmol, respectively. In normal rats, [18F]FDPA showed a high and stable cardiac uptake and fast clearance from other organs. In MI rats, NSRs in the peri-infarct and infarct regions, which were infiltrated with massive inflammatory cells revealed by pathology, were higher than that in the remote region (1.20 ± 0.01 and 1.08 ± 0.10 vs. 0.89 ± 0.05, respectively). [18F]FDPA was automated synthesized with high RCYs and molar activities. It showed a high uptake in inflammation regions and offered a wide time window for cardiac imaging, indicating it could be a potential cardiac inflammation imaging agent.
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Affiliation(s)
- Tiantian Mou
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Jing Tian
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Yi Tian
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Mingkai Yun
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Junqi Li
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Wei Dong
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Xia Lu
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Ziwei Zhu
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Hongzhi Mi
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China
| | - Xiaoli Zhang
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China.
| | - Xiang Li
- Department of Nuclear Medicine, Beijing Anzhen Hospital, Capital Medical University, No. 2 Anzhen Road, Chaoyang District, Beijing, 100029, China.,Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
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